Removable bridging plug for oil wells



Feb. l1, 1941.. M. E. NoRRls nMovAgLn BRIDGING PLUG Fon on. WELLS FiledJn. 22. 1940 www.

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Mortimer E. Norris, Balrerseld, Calif.

Application January 22, 1940i, Serial No. 314,989

4 Claims; (Cl. 166-13) My invention relates to a bridging vplug for oiland gas wells and has for its principal objects, to generally improveupon and simplify the construction of the bridging plugs now in generaluse, to provide a plug having a chamberedA flexible member that iscapable of being expanded as aresult of pressure pumped into the chamberor chambers within said flexible member and which member, when expanded,adjusts itself to the irregular surface of the well hole and provides aiiuid pressure uight joint between the plug and the hole and further, toprovide a bridging plug of the character referred to that may beeasily-and conveniently run into the hole, expanded and afterwardswithdrawn from the hole, and the use of which plug greatly facilitatesthe functionsincident to the testing of the formations throughout thelength vof the well hole and at the same time eliminating thetroublesome and expensive cementing jobs that usually attend testingoperations or the plugging of the well hole at different elevations.

A further object of my invention is, to provide a relatively simple andhighly eilicient bridging plug that is expanded by uid pressure so as tocompletely bridge or seal the well hole at any desired point and saidplug having associated therewith valvular means for controlling the uidpressure utilized in expanding the plug andkalso for controlling anyrelatively high pressures that may develop in that? portionV of the wellhole below the plug.-

With the foregoing and other objects in view, my invention consists incertain novel features of construction and arrangement of parts thatwill be hereinafter more fully described and claimed and A.illustratedin the accompanying drawing in which:

Fig. lis a vertical section taken lengthwise through the center'o myimproved plug and showing. the same positioned in a well hole.

Fig. 2 is an enlarged horizontal section taken on the line 2-2 of Fig.1.

Fig. 3 is a detail section of a punch pin that is i utilized forunseating the check valve that is positioned at the upper end of theplug.

Fig. 4 is a horizontal section taken on the line of Fig. 3.

Fig. 5 is a vertical section taken through the center of a box orcoupling that may be used immediately above the plug and which boxcon-y, tains a check valve utilized for controlling the circulatingiiuid that is pumped into the well hole.

Fig. 6 is a vertical section taken lengthwise through the center of amodiiied form of the plug and which is used in making tests in the wellhole.

Referring by numerals to the accompanying drawing and particularly tothe form of expanding plug illustrated in Figs. 1 to 5 inclusive, Idesignates a metal tube that functions as a carrier for the variousparts of the plug and the upper end of this tube is externally threadedso as to be screw-seated in the internally threaded lower portion of acombined coupling and valve housing Il. t

. Arranged within memberJl isa partition Iz having an aperture that isnormally closed by anupwardly seating check valve I3 and the latterbeing normally held on its seat by an expansive coilspring Il. The lowerend of this spring Hi rests on a partition I5 that is formed in thelower portion of member II and which isprovided with a series ofapertures I6. ,I

-The internally threaded upper end portion of coupling I2 is adapted toreceive the threaded lower end of a. drill 'pipe Il or the like andwhich serves to lower the plug into the well hole and to lift ittherefrom.

The externally threaded lower end of tube ID is screw-seated in `acombined valve housing and coupling member I8 within which is formed apartition i9 having an opening and normally resting on top of saidpartition I9 and closing the opening therein is a downwardly seatingcheck valve 2t that is yieldingly retained on its seat by an expansivecoil spring 2|. The upper end of the coil spring bears against apartition 23 that is formed within the housing I8 and said partitionbeing provided with apertures 24. The internally threaded lower portionof the coupling member I8 receives the threaded upper end-of acirculation tube 25.

Positioned upon the tube IIJ between the coupling members II and I8 is asubstantially cylindrical body 26 of rubber or composition of whichrubber is the principal ingredient and formed in the central portion ofthis body adjacent the tube II) is an angular chamber 21 that hascommunication with the passage through tube I0 by means of apertures 28that are formed in the wall of the tube. Expansible body 26 is securelyYanchored to tube Ill by means of flanges 29 that are formed on said tubeII), which anges are preferably dovetail in cross section and whichproject into the body 26 above and below the chamber 2h The end portions35, of the `expamsible lbody 25 are tapered and enclosing same are metalcaps 3| that taper slightly toward their outer ends.

Nuts 32 are screw-seated on the threaded portions of tube I0 and whensaid nuts are tightened against the ends of the caps 3|, the latter areclamped against the-tapered ends of body 26,

thereby cooperating with the dovetailed anges 29 in anchoring saidbodylto tube Ill. The expansible body 26 may be of any desired length.

In Fig. 5 I have illustrated a downwardly seating check valve that maybe utilized in the line I1 above the valve I3 for the purpose ofcontrolling the circulation in its ow through the well hole and thedrill pipe and also for controlling pressures that may develop in thewell hole adjacent the plug.

' This valve includes a housing 33 that is located in the line I1 abovehousing II and seated in the wall of said housing midway between itsends is the lower outer end of an elbow fitting 34, the upper inner endthereof being provided with a valve seat 35. Adapted to rest on saidvalve seat is aball check valve 36 from the top of which projects ashort stem 31 carrying on its upper end a head or knob 38 that isadapted to be engaged by a conventional expanding socket 39 and whichlatter may be run into the line I1 by means of a sand line or the like.I

For the purpose of unseating check valve I3 to relieve the pressure inthe chamber 21 of the expanding member 26 in order that the plug may bepulled from the well, a ring 40 is seated in the lower end of the lineI1 and said ring being provided with a spider 4I from which depends ashort pin or finger 42.

Thus when the line I1 carrying the ring 40 and pin 42 is lowered intotheWell hole for the purpose of removing the plug and vthe lower end ofline I1 is screwed into the` upper end ofthe' valve housingI II, finger42 will unseat check valve I3, thus permitting pressure from the chamber21 and within the tube I0 above the downwardly seating check valve 20,to pass upwardly into line I1 past the open valve I3.

- In the use of the form of bridging plug just described, the drill tube.or line that carries the plug is lowered into the well to the desireddepth with the expansible body 26 deated andy circulation under pressureis now pumped downwardly through the line I1 and passes fromP tube II!through the apertures 28 into chamber 21 so thaty that portion of member26 between the caps 3| will be expanded so as to make close contact withthe adjacent surface of the well hole or with the inner face of .thecasing in the event V-that casing has been runlinto the hole and thus,the ow or passage of oil, liquids, and gas through the well hole pastthe expanded member 26 is effectually prevented. The pressure pumped'downwardly through line I1 will open the upwardly seating check valveI3, but cannot pass downwardly seating check valve^20.

In the event that pressure develops in the hole below the plug and suchpressure exceedsthe the latter is lowered into the well and when thelower end of the line is screwed into the valve housing II, pin 42 willunseat check Valve I3, thereby relieving the pressure within the chamber21 and permitting vthe expanded portio'n of the body 26 to collapse andin such condition to be drawn from the well. v

When the valve structure, Fig. 5, is used, the housing 33 is located inline I1 above the valve housing Il and without the ball check valve 36,the plug and valve housing are lowered into thc well to thedesiredposition. Circulation pumped downwardly through line I1 will dischargeoutwardly through elbow tting 34 and now downwardly past the-unexpandedplug` into the lower portion of the well hole.

The use of the valve housing 33 and elbow 34 enables any liquid that mayoccupy that portion of the well hole into which the plug is positioned,

to flow upwardly through elbow fitting 34 into the pipe I0 and into theline I1.

Before starting the pump to force circulation fluid under pressuredownwardly through line I1 to expand member 26, ball 36 is dropped intoline I1 and after passing downwardly therethrough will rest on seat 35,thus providing a downwardly seating check valve and the circulationfluid under pressure will then flow from line I1 downwardly through thevalve housing 33 into tube I0 and from thence into the chamber 21 toexpand member 26.

To lift the check valve 36 from its seat and remove the same from theline, a' conventional expanding socket 39 is applied to the lower end ofa sand line or the like and lowered into the line I1 until said socketengages the head 38 on the stem 31 that projects upwardly from ball 36.

In Fig. 6 I have shown a form of plug that is especially'designed foruse in testing operations and this form of plug comprises an expansiblebody 43 of 3yrubber, having a centrally arranged chamber 44 and saidbody being anchored on a tube 45 with the ends of said body occupyingcaps 46 that are held in position by nuts 41 screwed onto tube 45.

Located in tube 45 below the expanding body 43 is a downwardly seatingcheck valve 48 that performs the same functions as check valve 2Upreviously described.

Formed through the wall of tube 45 within chamber 44 are apertures 49that are normally closed by spring pressed ball check valves that arearranged for operation within a valve housing 5I and which latter issecured to tube '45 around the openings 49 therein.I

Formed in valve housing 5I are apertures 52 that establish communicationbetween the chamber within the valve housing and the chamber 44 inexpansible member 43.

In the use of the plug just described, the line 45 carrying the plug isrun into the well hole to the desired depth and any iluid or pressure inthe well'hole below the plug will flow upwardly past check valve 48 andthence upwardly through the line 46. When it is desired to expand theplug, pressure is pumped downwardly through line 45 and such pressurebeing unable to pass downwardly seating check valve 48 will unseatvalves 50 and flow through openings 49, thence through the openings 52in valve housing 5I, thereby filling chamber 44 and expanding member 43until the same is forced into close contact with the adjacent surface ofthe well hole.

After the tests have been made, a. swa'ge is run downwardly through tube45 so as to engage and unseat check valves and the pressure within thechamber 44 is now free to ow through the openings 49 into tube V42',thereby relieving the pressure in chamber 44 and permitting member 43 toreturn to its normal position.

When member 43 is expanded, the passage of liquid within the well holeabove the plug downwardly into the well hole past saidplug, iseffectually prevented. v f

'Thus it, will be seen that I have provided a removable bridging plugfor oil wells that is relatively simple in construction, inexpensive ofmanufacture and very effective in performing the functions for which itis intended.

Among theparticular advantages of my improved plug are, the ability toconveniently raise and lower the plug 'to any desired point in the wellfor the purpose of making tests and for the bridging or plugging of thewell 'hole at any scope` of which' is set forth in the appended claims.,

I claim as my invention: A

l. A bridging plug for oil wells comprising a tube provided in its wallwith 'an opening, an. expansible member anchored on Asaid tube, saidexpansible member having a chamber that com-l municates with the'opening in the wall of the tube, an upwardly seating check valvein thetube above the expansible member, a downwardly seating check valve insaid tube below said expansible member, a valve housing in the tubeabove said upwardly seating check valve, a tubular tting within saidvalve housing, said tting having an opening on the side of said valvehousing communicating with the exterior of the tube 'and a valve seatwithin said valve housing .on the inner end of said tting and a valveremovablypositioned -on said valve seat.

2. In a bridging plug for oil wells, a tube provided in its wall with anopening, an expansible member positioned on said tube and provided witha chamber that communicates with the' housing located in said tube abovesaid expansible member, a tubular elbow fitting having one end seated inthe wall of said valve housing, the other end of said tting beingprovided' with a. valve seat, a valve adapted to rest on -said valveseat and a stem projecting upwardly from said valve.

MORTIMER E. NORRIS.

